1. Field of the Invention
The present invention relates to rice extracts for treating leukemia, especially relates to a rice prolamin that inhibits growth of leukemia cancer cells and induces differentiation of leukemia cancer cells through activating mononuclear cells.
2. The Prior Arts
Oryzae sativa (rice), one of the most important staple foods worldwide and the most commonly cultivated staple food in Taiwan, is rich in starch, protein (mainly the storage proteins), vitamins and minerals that provide essential nutrients to support human growth. In addition to its nutrition value, researches have shown that rice has many biological active ingredients. For example, flavonoids in rice can regulate cytochrome P450 activity (Noda, H., and Koizumi, Y. 2003. Sterol biosynthesis by symbiotes: cytochrome P450 sterol C-22 desaturase genes from yeastlike symbiotes of rice planthoppers and anobiid beetles. Insect Biochemistry & Molecular Biology. 33(6):649-58). Rice lipids contain anti-fungal active ingredients (Paranagama, P. A., Abeysekera, K. H., Abeywickrama, K., and Nugaliyadde, L. 2003. Fungicidal and anti-aflatoxigenic effects of the essential oil of Cymbopogon citratus (DC.) Stapf. (lemongrass) against Aspergillus flavus Link. isolated from stored rice. Letters in Applied Microbiology. 37(1):86-90). Rice bran can lower blood cholesterol (Qureshi, A. A., Sami,
S. A. Salser, W. A., and Khan, E A. 2002. Dose-dependent suppression of serum cholesterol by tocotrienol-rich fraction (TRF25) of rice bran in hypercholesterolemic humans. Atherosclerosis. 161(1):199-207), enhance natural killer cell activity of aged mice (Ghoneum, M., and Abedi, S., 2004. Enhancement of natural killer cell activity of aged mice by modified arabinoxylan rice bran (MGN-3/Biobran). J. Pharm. Pharmacol. 56, 1581-1588), and induce apoptosis of human endometrial adenocarcinoma cells (Fan, H., Morioka, T., and Ito, E., 2000. Induction of apoptosis and growth inhibition of cultured human endometrial adenocarcinoma cells (Sawano) by an antitumor lipoprotein fraction of rice bran. Gynecol. Oncol. 76, 170-175).
Leukemia, also known as blood cancer, is the number one childhood cancer and up to 40% of childhood cancer is leukemia. Major causes of leukemia are related to lymphoid progenitor cells, affected by factors such as genetic inheritance, virus infection and medication, which become abnormally differentiated hematopoietic stem cells and lead to excess production of immature white blood cell in blood stream or bone marrow.
Although currently there have been great improvements in leukemia treatment, severe side effects and high recurrence rate are still the main difficulties to be overcome for complete treatment of the disease. Because of low curing rate of leukemia, development of novel effective therapeutics with small side effects remains an unmet medical issue.